This invention relates to biodegradable lubricant compositions made from vegetable oil triglycerides and also pour point depressants and amine antioxidants. These lubricant compositions can be used for lubricating engines, transmissions, gear boxes, and for hydraulic applications. These compositions provide antioxidant stability as well as cold temperature performance. These compositions can also be used as a base stock for biodegradable greases or any other biodegradable lubricant compositions requiring oxidation stability and cold temperature stability, such as a penetrating composition and a metal working composition.
Vegetable oils are obtainable in large volumes from renewable resources and in general are characterized as readily biodegradable or xe2x80x9cenvironmentally friendly.xe2x80x9d As a result, such oils are potentially attractive for use in a wide variety of applications.
With respect to use for lubrication purposes, vegetable oils have not been fully desirable. Many vegetable oils do not possess the desired spectrum of characteristics relating to: pour point; oxidative stability; and compatibility with additives among others. Vegetable oils do however possess many desirable properties for use as a lubricant. In particular, vegetable oils typically provide good boundary lubrication, good viscosity, high viscosity index and high flash point. In addition, vegetable oils are generally nontoxic and readily biodegradable. For example, under standard test conditions (e.g., OCED 301D test method), a typical vegetable oil can biodegrade up to 80% into carbon dioxide and water in 28 days, as compared to 25% or less for typical petroleum-based lubricating fluids.
U. S. Pat. No. 4,783,274 (Jokinen et al., Nov. 8, 1988) is concerned with an anhydrous oily lubricant, which; is based on vegetable oils, which is substituted for mineral lubricant oils, and which, as its main component, contains triglycerides that are esters of saturated and/or unsaturated straight-chained C10 to C22 fatty acids and glycerol. The lubricant is characterized in that it contains at least 70 percent by weight of a triglyceride whose iodine number is at least 50 and no more than 125 and whose viscosity index is at least 190. As its basic component, instead of or along with the said triglyceride, the lubricant oil may also contain a polymer prepared by hot-polymerization out of the said triglyceride or out of a corresponding triglyceride. As additives, the lubricant oil may contain solvents, fatty acid derivatives, in particular their metal salts, organic or inorganic, natural or synthetic polymers, and customary additives for lubricants.
U. S. Patent No. 5,298,177 (Stoffa Mar. 29, 1994) discloses a functional fluid comprising
(A) at least one triglyceride;
(B) at least one detergent-inhibitor additive; and
(C) at least one viscosity modifying additive and further comprising (D) at least one synthetic oil.
U. S. Patent No. 5,388,471 (Lal, Aug. 16, 1994) relates to vegetable oils that possess at least 60 percent monounsaturation content, vegetable oils that are transesterified and contain at least one pour point depressant. In addition to pour point depressants, the vegetable oil and transesterified product also contain a performance additive designed to enhance the performance of the vegetable oil and transesterified product when used in hydraulic fluids, two-cycle (two stroke) internal combustion engines, gear oils and passenger car motor oils.
U.S. Pat. No. 5,399,275 (Lange et al., Mar. 21, 1995) relates to triglyceride oils having viscosity index improving characteristics wherein the triglyceride oils contain at least a 60 percent monounsaturated content. Triglyceride oils containing this viscosity index improver have utility in passenger car motor oils (PCMO), gear oils, automatic transmissions fluids (ATF), hydraulic fluids, chain bar lubricants, way lubricants for machinery operations, diesel lubricants and tractor fluids.
U.S. Pat. No. 5,413,725 (Lal et al., May 9, 1995) is directed to vegetable oils that possess at least 60 percent monounsaturation content and contain at least one pour point depressant. In addition to pour point depressants, the vegetable oil may also contain a performance additive designed to enhance the performance of the vegetable oil when used in hydraulic fluids, two cycle (two stroke) internal combustion engines, gear oils, and passenger car motor oils. U.S. Pat. No. 5,538,654 (Lawate et al., Jul. 23, 1996) describes a food grade lubricant composition which is useful as hydraulic oil, gear oil, and compressor oil for equipment in the food service industry. This composition comprises (A) a major amount of a genetically modified vegetable oil and (B) a minor amount of a performance additive. In other embodiments the composition contains either (C) a phosphorus compound or (D) a non-genetically modified vegetable oil.
U.S. Pat. No. 5,641,734 (Naegely, Jul. 24, 1997) describes a lubricant composition which is useful as a chain bar lubricant for chain saws. The composition comprises
(A) at least one triglyceride wherein the ratio of the oleic acid moiety:linoleic acid moiety is from about 2 up to about 90,
(B) at least one viscosity modifying additive, and
(C) at least one tackifier.
Optionally, the composition may also contain
(D) at least one pour point depressant and
(E) at least one antiwear agent.
A composition, comprising;
(A) at least one triglyceride oil of the formula 
wherein R1, R2 and R3 are aliphatic hydrocarbyl groups containing from about 7 to about 23 carbon atoms;
(B) a pour point depressant comprising
(1) an alkylated polystyrene or
(2) a polyalkyl methacrylate; and
(C) an antioxidant comprising an amine of the formula 
and R5 is hydrogen, an alkaryl group or an aralkyl group, R6 is an aryl group, an alkaryl group or an aralkyl group, with the proviso that when R5 is hydrogen, then R4 is an aryl group.
Optionally, the (A), (B) and (C) composition may further comprise
(D) other oils comprising
(1) a synthetic ester base oil or (2) a polyalphaolefin.